DE 44 00 487 A1 discloses fluid cooling devices, also called pneumatic coolers, incorporated as compact modular units in hydraulic or liquid circuits in plants or machines. The liquid cooling is generally dependent on the input temperature differential between liquid and ambient air, on flow volume and on the flow rate of the air. Heating problems arising as a result of multi-layered operation and higher air temperature could consequently be prevented. In order to be able to use such fluid cooling devices for hydraulic work cycles of greater magnitude, the oil reservoir must be enlarged to a correspondingly large-dimensioned volume.
DE 43 37 131 A1 involves a design of a hydraulic assembly, for the enlargement of the oil reservoir volume, including a hollow capsule around a motor and pump unit of the hydraulic assembly. This design clearly complicates the free passage, for example for assembly and maintenance purposes, from the exterior to the motor and pump unit of the hydraulic assembly.